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An efficient, highly convergent route for the synthesis of novel fourteen single isomer derivatives of ethyl-2-methyl-4-(pyridin-2-yl)-4H-benzo[4,5]thiazolo[3,2-a]pyrimidine-3-carboxylate have been developed by one-pot, three-component reaction between pyridine 2-aldehyde, β-ketoester and various derivatives of 2-amino benzothiazole in the presence of D-(+)-10-camphorsulphonic acid (D-(+)-10-CSA) as an effective chiral acid catalyst. Under the optimized conditions with 20 mol% catalyst loading, a wide range of optically active 4H-pyrimido[2,1-b]benzothiazole derivatives were obtained in good yields (up to 82%) with good to excellent enantioselectivities (84-99%ee). Their structures were elucidated by various spectroscopic methods such as 1H-NMR, 13C-NMR, Chiral HPLC, mass and elemental analysis. The attractive feature of this approach is one-pot synthesis, good yield, environment benign, mild reaction condition, simple, efficient, excellent stereoselectivity, water soluble catalyst and easy workup. All the final scaffolds have been screened for antibacterial activity. Among them, 4a', 4c', 4d', 4e', 4f', 4g', 4j',4m' and 4n' were proven to possess enhanced antibacterial properties as compared to the standard drug. [ABSTRACT FROM AUTHOR]

A simple and green method was developed for the reaction of 2-aminothiophenol and benzaldehyde in the self-neutralizing acidic CO2-alcohol system to produce benzothiazoles. A series of benzothiazole derivatives were successfully prepared from the condensation and cyclization reaction of 2-aminothiophenol or substituted 2-aminothiophenol with aliphatic, heteroaryl and aryl aldehydes promoted by alkyl carbonic acid under mild conditions. Moreover, the method is also suitable for the synthesis of 2-phenylbenzimidazole and 2-phenylbenzoxazole. Additionally, this reaction system greatly simplified post-processing, which did not need to be neutralized with base and without salt disposal. These advantages make the process more practical, economical, and environmentally friendly. Mechanism investigation indicated that formation of alkyl carbonic acid from CO2 and methanol is the key intermediate, which provides hydrogen ions to catalyze the reaction of 2-aminothiophenol and benzaldehyde. [ABSTRACT FROM AUTHOR]

A series of benzothiazole derivatives bearing a 1,3,4-thiadiazole moiety were designed, synthesized and evaluated for their antibacterial, antifungal and antiviral activities. The bioassay results indicated that most of target compounds showed good antiviral activities against tobacco mosaic virus (TMV) and antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo) and Ralstonia solanacearum (Rs). Especially, the anti-Xoo effect of title compounds 5k (N-(5-methoxybenzo[d]thiazol-2-yl)-2-((5-(2-tolyl)-1,3,4-thiadiazol-2-yl)thio)acetamide) and the anti-Rs effect of title compounds 5a (N-(5-nitrobenzo[d]thiazol-2-yl)-2-((5-(4-(trifluorom ethyl)phenyl)-1,3,4-thiadiazol-2-yl)thio)acetmide) respectively reached 52.4% and 71.6% at 100 µg/mL, which are superior to that of bismerthiazol (32.0% and 52.3%). In addition, the protective and inactivation activities of title compound 5i (N-(5-methoxybenzo [d]thiazol-2-yl)-2-((5-(4-nitrophenyl)-1,3,4-thiadiazol-2-yl)thio)acetamide) against TMV were 79.5% and 88.3%, respectively, which are better than that of ningnanmycin (76.4% and 86.8%). The above research showed that benzothiazole derivatives bearing a 1,3,4-thiadiazole moiety may be used as potential molecular templates in searching for highly-efficient antiviral and antibacterial agents. [ABSTRACT FROM AUTHOR]

Sixteen new 2-(benzothiazol-2-ylthio)-N′-(3-substituted-4-(3,4-substitutedphenyl)thiazol-2(3H)-ylidene)acetohydrazide derivatives (4a-4p) were synthesized. The structures of the synthesized compounds were elucidated using FT-IR, 1H-NMR, 13C-NMR, and HRMS spectral data. Anticancer activity of the compounds 4a-4p against C6 (rat brain glioma) and A549 (human lung adenocarcinoma) cell lines was evaluated by using MTT, inhibition of DNA synthesis, and flow cytometric analysis assays. According to MTT assay, 4a and 4d were found to be the most active compounds against C6 cell line with an IC50 value of 0.03 mM. Moreover, IC50 values of 4a (0.2 mM) and 4d (0.1 mM) against NIH3T3 (mouse embryo fibroblast cell line) were higher than their IC50 values (0.03 mM) against C6 cell line. Accordingly, selectivity of compound 4a against C6 cell line was two-fold higher than that of compound 4d. Flow cytometry analysis showed that these compounds display anticancer activity by inducing apoptosis. As a result, compound 4a has a remarkable anticancer activity and a good selectivity towards C6 cell lines. [ABSTRACT FROM AUTHOR]

A series of novel a-aminophosphonates containing 6-fluorobenzothiazole moiety derivatives were synthesized by one-pot reaction under microwave irradiation and their structures were characterized by IR,1H,13C, and31P NMR and element analysis data. Antiviral assays showed that some compounds possess good curative and protective activities against tobacco mosaic virus (TMV)in vivoat 500 µg/mL In particular, compounds diethyl [(6-fluorobenzo[d]thiazol-2-ylamino)(phenyl)methyl]phosphonate (4b), diethyl [(6-methoxybenzo[d]thiazol-2-ylamino)(thiophen-2-yl)methyl]phosphonate (4j) and diphenyl [(6-fluorobenzo[d]thiazol-2-ylamino)(4-methoxyphenyl)methyl]phosphonate (4q) exhibited remarkable antiviral activities than Ribavirin against TMV and PVY. Compound diphenyl [(6-fluorobenzo[d]thiazol-2-ylamino)(4-methoxyphenyl)methyl]phosphonate (4q) showed similar curative and protective activity against potato virus Y (PVY) to Dufulin. [ABSTRACT FROM AUTHOR]

Two methodologies to access S-heterocycles and mixed N,S-heterocycles via metal-mediated domino reactions are described. One involves a cyclocarbopalladation/cross-coupling domino process and leads to benzene-fused five- or six-membered sulfur heterocycles with a stereo defined tetrasubstituted exocyclic double bond. The other consists in a three-component domino reaction between 2-aminophenyl disulfide, copper cyanide, and an electrophile to access N-substituted 2-amino benzothiazoles. Preliminary results in the use of the second method to access N-substituted 2-imino benzothiazoles are also reported. [ABSTRACT FROM PUBLISHER]

The synthesis of 2-(substituted phenyl)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (A1-A24) derivatives and 2-(4-substituted thiazol-2-ylamino)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (B1-B14) derivatives was undertaken starting from the potassium salt of 4-(2-pyrimidinyl)piperazine dithiocarbamate. The structures of the obtained compounds were elucidated by1H NMR,13C NMR, MS spectral data, and elemental analysis. The antimicrobial activity of the thirty eight newly synthesized compounds were tested against 12 microorganism strains using the microdilution technique. Compounds 2-(4-ethoxycarbonylthiazol-2-ylamino)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (B12), 2-(3-fluorophenyl)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (A18) and 2-(3,4-difluorophenyl)-2-oxoethyl 4-(pyrimidin-2-yl)piperazin-1-carbodithiodate (A21) were determined to possess high antimicrobial activity. [ABSTRACT FROM AUTHOR]

Nano-titania-supported sulfonic acid (n-TSA) has been used as an efficient, inexpensive and reusable heterogeneous nano catalyst for synthesis of 2-arylbenzothiazole derivatives under solvent free condition. The reaction works very well, with good to excellent yields, for different aromatic aldehydes with both electron-withdrawing and electron-donating groups. Easy preparation and separation of catalyst, simply workup procedure, clean reaction, and reusability of the catalyst up to seven times without appreciable loss of its catalytic activity are undoubtful advantages of this work. [ABSTRACT FROM PUBLISHER]

new synthetic method for the synthesis of benzothiazoles via PCl3 and DBU promoted cleavage/acylation/cyclization tandem reaction of disulfides and aromatic carboxylic acids has been developed. PCl3 acted as both an acylating reagent and a disulfide cleaving reagent, which promoted disulfides of 2-aminobenzenethiol to react with aromatic carboxylic acid to produce benzothiazole derivatives. [ABSTRACT FROM AUTHOR]

Benzothiazolyl 2-hydroxyethyl sulfoxide (1a) was found to afford bis[2-(2-oxobenzotiazolyl)-ethyl] disulfide (2a) in the presence of DBU at rt. 2a was formed by the condensation of corresponding sulfenic acid intermediate. Thermolyses of 1a in the presence of ethyl propiolate at 60-140°C were carried out to succeed to trap sulfenic acid 6a as an intermediate. Trapping of 2-benzothiazolyloxyenthanesulfenic acid (6a) revealed that the thermal reaction proceeded via a five-membered spiro intermediate 5a. [ABSTRACT FROM AUTHOR]

A mild and efficient methodology to produce 2-mercaptobenzothiazoles in DMF via ortho-haloaniline coupling with potassium O-ethyl dithiocarbonate catalyzed by copper without a ligand has been developed. [ABSTRACT FROM PUBLISHER]